GLOUCESTER, Mass. (AP) — A pact made by a group of teens to get pregnant and raise their babies together is at least partly behind a sudden spike in pregnancies at Gloucester High School, school officials said.

Principal Joseph Sullivan told Time magazine in a story published Wednesday that the girls confessed to making the pact after the school began investigating a rise in pregnancies that has left 17 girls at the school carrying a child. Normally, there are about four pregnancies a year at the school.

Sullivan told Time that nearly half of the expecting students, none over 16, were involved. Sullivan said students were coming to the school clinic multiple times to get pregnancy tests, and “seemed more upset when they weren’t pregnant than when they were.”

Some of the girls reacted to the news they were pregnant with high fives and plans for baby showers, Sullivan said. One of the fathers “is a 24-year-old homeless guy,” Sullivan told the magazine.

Superintendent Christopher Farmer confirmed the deal to WBZ-TV, saying the girls had “an agreement to get pregnant.”

He said the girls are generally “girls who lack self-esteem and have a lack of love in their life.”

Mayor Carolyn Kirk told The Associated Press on Friday that many factors are involved in the surge in pregnancies in her community, a hardscrabble fishing village which has fallen on tough economic times and cut teachers and services, including some health classes.

“I don’t think there was a pact in the order of a dozen girls conspiring to get pregnant. That would really surprise me, and I have seen no evidence of it,” she said.

Christen Callahan, a former Gloucester High School student who had a child when she was 15, said on NBC’s “Today” show that some of the girls would ask her about her own pregnancy.

“They would say stuff like, oh, I think my parents would be fine with it and they would help me, stuff like that,” Callahan said.

But she said she had no firsthand knowledge of a pact between the girls to get pregnant.

“They were just kind of like curious about it, they never actually came out and said it,” Callahan said.

The first reports of the students’ apparent plan to get pregnant were in the Gloucester Daily Times in March, when Sullivan said students were reporting that the girls were getting pregnant on purpose.

The rash of pregnancies has shaken the seaside city about 30 miles north of Boston. Last month, two officials at the high school health center resigned to protest the resistance from the local hospital to the confidential distribution of contraceptives. The hospital administers the state money that funds the clinic.